slow running 2

[timetc]

Perhaps no-one uses members technical so I will try here
having fun with getting slow running 27 flyer and banbury looming
two turns out on pilot jet now
cast alloy silencer to 2″ pipe plus howeth silencer with plain 1-1/4 outlet no fishtail
timing twixt 1/4 and 5/16 fully advanced new engine about 3 road miles running (push start) faint smoke from pipe (still adding some oil to petrol) just dies when throttle closed. carb clean cannot see any leaks rebuilt mag
6/4 slide ordered a 6/3 but thats not problem run out of ideas except keep ridingtimetc

Update:
200 main up from 180 jet 106 needle
checked transfer and crankcase door seals all OK reduced the running in oil content of petrol to a smidgen
a 10-15 ft push in botton and she starts and runs fine in fact much faster than I anticipated smooth turbine feel no misfires comes off choke in a mile
BUT just refuses to start on kickstart and will not run down to a tick over whatever pilot screw says I begin to think I shall be on a Douglas in a week or so time…

[pplatt]

I know very little about Scotts (but I’m learning loads!) but I do find myself asking a couple of questions…

Has your bike always had this problem? If not, what changed before the problem surfaced?

Also, how is the throttle stop adjusted (if there is one on a 2 speeder!). Is it set up so the throttle is totally closed? I only ask this because I have read that some folks set there bikes up this way to eliminate surging on the overrun.

I’m sure there are folks in here who will be able to give you much more helpful pointers but maybe I have started the ball rolling….

-Cheers,

Pete P.

P.S. What number have you got for Banbury? I’ll find you and say hi if I make it to the event (as a spectator, my Scott is a ’36)

[BRIAN MARSHALL]

I assume that you have an Amal Carb ? If so, you need to be raising the throttle stop screw, not tweaking the pilot mixture. Slacken off the throttle stop lock-nut, and then with your finger feeling the airslide, screw the throttle stop screw in until you feel the slide being lifted up. Raise it about a sixteenth of an inch, and then start the engine, adjusting the screw until you get a tickover.
As regards not starting on the kickstart, I wonder if you are using the correct technique…. Again assuming that you have an Amal carb, the technique for starting from cold is to first turn on the oil tap, then the petrol tap, and depress the tickler button until petrol dribbles out of the vent hole on top of the float chamber. Close the air lever, and then give one kick with the throttle closed in order to draw some mixture into the crankcase. Then open the throttle around a quarter to a third open, and operate the kickstart with the proverbial “long swinging kick”. There should be no need to retard the ignition.
Try this and let us know how you get on….
Brian

PS There remains the possibility of a blocked primary airway in the carburettor. Some of the drillings are very fine, easy to miss when checking the carb, and equally easy to get blocked. You can poke them through with the bristle cut from a wire brush, or even better, go to a BOC depot and buy one of their excellent sets of jet cleaning wires sold to clean out gas welding nozzles. Roger Cooper was recently having endless problems getting his vintage Flyer to run properly, tried endless things, and finally discovered a blocked primary airway in his carb..

[timetc]

Update
I took the carb off –(quite a success I only lost one ¼ washer to the crankcase) I poked the requisite holes with a wire – an act of faith since I could not tell if any were blocked. Checked the slide lift on the screw was 1/16 fitted new carb port gasket
Only lost one more washer putting carb back 🙂
Carried out procedure, kicked till I lost all feeling in leg.
I shall clean plugs drain crankcase (in case its grunged up) check sparks and wait for a either a pusher or some quick start But it begins to look like I had better spend some time on the Belt drive Douglas for Banbury (that started straightaway after 18 months) . pushers are thin on the ground in rural Oxfordshire.In any case 4 miles since it was built is not sufficient testing miles to ensure reliability. this week end it must be sorted or I must make my decision. my next big event is the KOP hill climb so I can only hope that things improve by then.
NB Interesting the difference in opinion about slide at rest position I had read don’t use the slide limit screw because of overrun but Mr Marshals 1/16 makes sense to me thinking about it

[BRIAN MARSHALL]

I’m now beginning to wonder about your ‘rebuilt’ magneto, and wonder if it is sparking at low rpm. Try reducing the spark plug gaps down to 10 thou, just as an experiment, and see if it improves things. Further to my previous comments, I am one who does not use the throttle stop, in order to get a jerk free over-run, but until you get used to starting and riding a Scott it will probably help you to use it to obtain a tickover. IF a squirt of ‘Easystart’ does help starting, I would still suspect your carb, and perhaps you could borrow a known good one and substitute it for yours.
I’ve only ever had one Scott that was a bad starter, and that was a pseudo Sprint Special that had been ‘tuned’ by having the ports modified to the point where it had got very poor suction at kickstart rpm.
Brian

[timetc]

Oh I havent given up yet Brian
I appreciate your suggestions, when it does get going it really flys along the road so perhaps sombody has been ‘at it’ although a few good men have seen the barrels and did not say the porting looked radical.
(For once in my 2 wheeled careeer speed is not that important!)
I have been here with other machines by the time you find the obsure reason and it works correctly you have renewed and checked everything and you end up with a well sorted bike
(Well thats how I will console myself) I will keep you all informed

[Author]

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